At least it is according to my Compact Dictionary of Exact Science and Technology, but I have seen it used on many occasions too

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Note added at 4 mins (2008-09-20 11:50:51 GMT)
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Or for your purposes - setting gemstones.

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Note added at 2 hrs (2008-09-20 13:55:28 GMT)
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This link shows that the mounting is the metal into which the gem is set, but that setting is the verb:

"Intro to Setting Gems
Snap-Tite Earring Setting
A setting is a metal form into which a gemstone is placed into jewelry. The metal, known as a mounting or finding in the jewelry trade, may be made of a precious metal like gold, silver or platinum; or some less valuable metal like tungsten steel or titanium.

The setting uses claws, prongs, a bezel, or other means to hold the gemstone in place securely. The task of setting a gemstone can be simple or complicated, depending on the size and shape of the gem and the type of setting.

The simplest case of setting a gemstone is one where a gemstone in a calibrated size is placed in a standard mass-produced setting. Some of these standard settings are designed for inexperienced consumers to use with only very simple tools required. Some cleverly designed mountings will snap shut once the gem is placed in the correct position and one only has to tighten the claws or prongs to ensure that the setting is secure. But most gemstone buyers still go to their local jeweler to have their gemstones set."

http://www.gemselect.com/other-info/gemstone-settings.php

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Note added at 4 days (2008-09-24 23:19:14 GMT) Post-grading
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Thank you, Shane